Method of making photographic packet emulsions



April 2, 1957 L. GODOWSKY ET AL COUPL ER LOW- BOILING SOLVENT COUPLER C OUPL ER COUPLER SOL VENT SOLU77ON COUPLER DISPERSION //v GELA TIN PARTORALL OF LOW- BOILINC SOLVENT MAY BE REMOVED GELAT/NO-SILVER HAL/DE EMULSION PACK E T DISPERSION OF COUPLER AND SILVER HAL/DE IN GELA TIN I-I/GH BO/L INS COUPL ER SOL VE N T PAC/(ET DISPERSION OF COUPLER, SILVER HAL/DE AND HIGH BOILING COUPLER SOLVENT IN CELAT/N LEOPOLD aboowsxr JEROME J DUA NE IN V EN TORS ATTORNEYS METHOD OF MAKING PHOTOGRAPHIC PACKET EMULSIONS Leopold Godowsky and Jerome J. Duane, Westport,

Conn., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation 'of New Jersey Application December 20, 1954., Serial No. 47 6 ,54 v

Claims. (Cl. 96-97) This invention relates to color photography and particularly to. a method for making packet emulsions.

In Godowsky U. S. Patent 2,698,794, a process is described. for making packet emulsions by dissolving a colorforming compound. in a high boiling crystalloidal organic solvent, for the. color former and dispersing it in a gelatinosilver halide emulsion and then forming packets with a polymeric packet-forming component such as the ammonium salt of styrene-nialeamic acid resin. Ratios of color former or coupler to coupler solvent of 'about 1:2 or 1:3; are usually employed and the high boiling solvent is retained in the final emulsion. i

In, packet photographic emulsions such as those of Patent 2,698,794, the character of the high boiling solvent has. a direct effect on the photographicproperties such as the stability of the packets, their developability, the hue of the dye formed upon exposure and development, the degree of color separation in the case of mixed packets and other properties.

We have foundthat if the coupler dispersion, that is, the packet dispersion containing the coupler'and' silver halide, is made without the high boiling crystall'oidal sol vent and the high boiling solvent is added aftercomplete formation of the packet emulsion, improved results are obtained. Packets which are formed in this wjayare better dispersed in the gelatin matrix or continuous phase than'when the high boiling solvent is added first, and bet: ter color separation is obtained" in the case of mixed packet-s. i

The accompanying drawingis a how sheet il lustrating the steps in our process. Y

Our'novel methods consists in (l) mixing the coupler with a low boiling organic solvent for'the coupler as shown in the first three boxes of the drawing, anddisp ersing the mixture in gelatin asshown in tlie fourth bo r of theidrawing, (2) mixing the coupler dispersion withasik ver halide emulsion and forming "a packet dispersion of the coupler and silver halide in 'gelatin;a s 'shown in the fifth box of the drawing, and (3') adding a highboilin'g coupler solvent to the packet dispersionasjshown in the last box of the drawing." In'thisway the. ratiolof, coupler to high boiling crystalloidal coupler solyent can: be readily adjusted so that any ratiobetween lfi andlflA orlower is obtained. 'Thismethlod not onlyperrnits improvedcolor separation to be obtainedwlien theliigh boiling solvent is added after formation of.the .pa ckets but it, also has: the advantage, that t'ofthe pa clretsfcon taining couplerwithout couplersolvept. any; number, of

we e. olve co ple o e t'i i tiersi se man be addedWo the packet dispersion without the necessity of i t di ates Par-em Patented Apr. 2, 1957 2 (2,4 di tert. amylphenoxyacetamino) 4,6 dichloro-S-methyl phenol (Graham U. 8. 2,725,291)

2 [a (2,4 di tertamylphenoxy) n butyrylamino] 4,6-dichloro-5-methyl phenol 1 hydroxy 2 [6 (2,4 di tertamylphenoxy) n-butyH-naphthamide (U. 8. Patent 2,474,293)

1 (2,46' trichlorophenyl) 3 [3 (2",4-' di tert.amylphenoxyacetamido) benzamido] 5 pyrazolone (U. S. Patent 2,600,788)

N (4 henzoylacetamidobenzenesulfonyl) N ('y phenylpropyl)-p-toluidine (U. S. Patent 2,298,443)

6 {at {4 [on (2,4 di tertamylphenoxy)butyramido] phenoxy} acetanlido} 2,4 dichloro 3 methyl phenol a {3 [on (2,4 di terLamylphenoxy) acetamido] benzoyl} 2 methoxyacetanilide 3 benzoylacetamino 4 methoxy 2',4 di tert.

amylphenoxy acetanilide The preparation of the last three couplers is described in Fierke and Chechak U. S. application Serial No. 476,561, filed concurrently herewith.

Low boiling organic solvents in which the coupler is first dissolved and which may then be removed partially or completely prior to making the packets includenitro methane, nitroethane, methyl, ethyl andpropyl acetates, chloroform, and ethyl and butyl formate.

High boiling coupler solvents which are added to the packet dispersions are organic crystalloidal materials which are substantially water-insoluble, have low molecular weight, have a boiling point above 175 C., and have a high solvent action for the color-forming compound. and for the dyes formed from it, and are permeable to photographic developer and its oxidation products. Such solvents include di-nrbutyl phthalate, triphenyl phosphate, tricresyl phosphate, N,n-butyl acetanilideand. other compounds disclosed on pages 2 and 3 of Jelley and Vittum U. S. Patent 2,322,027.

In making the packets the method described in Examples l5 and 16 of Godowsky U. 5. Patent 2,698,794 is preferably employed except that the high hoilingcrystalloidal solvent is not added to the coupler dispersion-or packet dispersion as in that application, but is separately dispersed andadded later. in forming the packets, a Wfl'telfiSOlllblQ poiymer such as the sodium salt of a copolymer of methacrylic acid? and methyl-wmethaerylate may be used together withv a packet-forming component such as the ammonium salt of styrene-maleamic acid to polymer. This type of water-soluble polymer is..not a necessity for the'formation of packets. Naturallyfoccurring .vater-soluble polymers and modified naturally occurring water solu ble polymers can also be used,.e. g., alginfcarboxy methylcellulose, and cellulose sulfate Our invention will now be, illustrated by the following examples:

E am e.

A cyan coupler dispersion was made by dissolving 3 grams of the coupler 2-[a-(2,4-di-tert-amylphenoxy)-n butyrylamino]-4,6-dichloro--methyl phenol in 300 cc. of ethyl acetate at 40 C., adding the solution to 100 cc. of a 5% solution of Alkanol B dispersing agent in 850 cc. of gelatin solution, and dispersing it therein. The dispersion was set on a chill plate at F., noodled and air dried at 78 C. and relative humidity. 16.5 grams of a red-sensitive gelatino-silver chloride emulsion containing 0.72 gram of silver halide and 0.40 gram of gelatin were added to 2.45 grams of the cyan coupler dispersion (redispersed in 12.0 cc. water), and mixed with a fast stirrer for 10 minutes. Thirteen cos. of a 10% solution of a copolymer of methacrylic acid and methyl-amethacrylate (sodium salt) were mixed with the emulsioncoupler dispersion and stirred for 10 minutes more. To this solution there were added 2.2 cc. of a 5.0% solution of the ammonium salt of styrene-maleamic acid polymer, and the whole dispersion was stirred at 40 C. for 20 minutes. Then 2.0 cc. of 10% calcium acetate solution was added followed by 5 cc. of an 18% gelatin solution.

To a portion of this mixture containing 0.12 g. of the cyan coupler there was added 1 cc. of a methyl alcohol solution containing 0.03 g. of di-n-butyl phthalate. After stirring for one minute at 40 C., the packet dispersion was examined under the microscope.

Microscopic examination revealed no evidence of particles of di-n-dibutyl phthalate, whereas a control dispersion without the packets showed a large number of droplets of di-n-butyl phthalate.

Example 2 A cyan packet dispersion was made as in Example 1. A magenta packet dispersion was similarly made, using 100 grams of the magenta coupler 1-(2',4',6'-trichlorophenyl)-3-[3"-(2",4"'-di-tert. amylphenoxy acetamido)- 5 CC. Di-n-butyl phthalate 6 Gelatin (10% solution) 27 Alkanol B (10% solution) 6 Water 2 dispersed in a colloid mill.

The amount of coupler solvent (di-n-butyl phthalate) dispersion added to the packet emulsions is such that the ratio of couplers to coupler solvent is about 1:1, in order to obtain adequate dye density in the resulting coating. However, ratios of coupler to coupler solvent of 1: /2, 1:% and even 1:0 can be employed with certain couplers or if a solvent such as benzyl alcohol is present in the developer. Higher ratios, such as 1:2, 1:3, etc., may also be employed.

Development of the coated and exposed layer in a primary aromatic amino developing solution such as the following, produced a two-color image of satisfactory dye density:

G. 2-amino-5-diethylamino toluene HCl 2 Sodium sulfite (des.) u 2 Sodium carbonate (anhydrous) 20 Potassium bromide 2 Water to 1 liter.

It will be understood that our invention may be em.- ployed in making packet dispersions in a layer in which the packet emulsion is sensitive only to a single primary spectral region, either in single layer or in multi-layer coatings, or may be used in making packets in which two or more sensitive packets are mixed in a single photographic layer.

The examples described herein are, illustrative only and our invention should be taken as limited only by the scope of the appended claims.

What we claim is:

1. The method of incorporating a color former in a photographic packet emulsion which comprises mixing a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, with a low boiling water-insoluble organic solvent for the color-forming compound, said low-boiling solvent having a boiling point below C., dispersing the solution of color-forming compound and low boiling organic solvent in gelatin, mixing the colorformer dispersion with a gelatino-silver halide emulsion, forming in a gelatin continuous phase, a packet dispersion of said emulsion and color-former, and then mixing said packet dispersion with a solution of a substantially water-insoluble, low molecular weight organic crystalloidal solvent for the color-forming compound and for dyes formed therefrom, and which solvent has a boiling point above about C. and is permeable to photographic developer oxidation products, to form a packet dispersion of said color-forming compound containing said crystalloidal solvent.

2. The method of incorporating a color former in a photographic packet emulsion which comprises mixing a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, with a low boiling water-insoluble organic solvent for the color-forming compound, said low-boiling solvent having a boiling point below 125 C., dispersing the solution of color-forming compound and low boiling organic solvent in gelatin, drying said dispersion to remove substantially all organic solvent, mixing the color-former dispersion with a gelatino-silver halide emulsion, forming in a gelatin continuous phase, a packet dispersion of said emulsion and color-former, with a styrene interpolymer having carboxyl groups on the polymeric chain, and then mixing said packet dispersion with a solution of a substantially water-insoluble, low molecular weight organic crystalloidal solvent for the colorforming compound and for dyes formed therefrom, and which solvent has a boiling point above about 175 C. and is permeable to photographic developer oxidation products, to form a packet dispersion of said color-forming compound containing said crystalloidal solvent.

3. The method of incorporating a color former in a photographic packet emulsion which comprises mixing a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, with a low boiling waterinsoluble organic solvent for the color-forming compound, said low-boiling solvent having a boiling point below 125 C., dispersing the solution of color-forming compound and low boiling organic solvent in gelatin, drying said dispersion to remove substantially all organic solvent, mixing the colorformer dispersion with a gelatino-silver halide emulsion, forming in a gelatin continuous phase a packet dispersion of said emulsion and color-former, with a styrene interpolymer having carboxyl groups on the polymeric chain, separately dispersing in gelatin a substantially water- Insoluble, low molecular weight organic crystalloidal solvent for the color-forming compound and for dyes formed therefrom, and which solvent has a boiling point above about 175 C. and is permeable to photographic developer oxidation products, and mixing said packet dispersion and said crystalloidal solvent dispersion to form a packet dispersion of said color-forming compound containing said crystalloidal solvent.

4. The method of incorporating a color former in a photographic packet emulsion which comprises mixing a color forming compound capable of reacting with a primary aromaticamino developing agent on photographic development, with ethyl acetate, dispersing the solution of color-forming compound and ethyl acetate in gelatin, drying said dispersion to remove substantially all ethyl acetate, mixing the color-former dispersion with a gelatino-silver halide emulsion, forming in a gelatin continuous phase a packet dispersion of said emulsion and color-former with the ammonium salt of a styrenemaleamic acid polymer, separately dispersing di-n-butyl 5 phthalate in gelatin, and mixing said packet dispersion and said di-n-butyl phthalate dispersion to form a packet dispersion of said color-forming compound and di-n-butyl phthalate.

5. The method of claim 4 in which the color-former is 10 2 [a (2,4 di tert. amylphenoxy) n hutyrylami no] 4,6 dichloro 5 methyl phenol.

References Cited in the file of this patent UNITED STATES PATENTS 2,322,027 Jelley et al. June 15, 1943 2,698,794 Godowsky Jan. 4, 1955 FOREIGN PATENTS 540,368 Great Britain Oct. 15, 1941 

1. THE METHOD OF INCORPORATING A COLOR FORMER IN A PHOTOGRAPHIC PACKET EMULSION WHICH COMPRISES MIXING A COLOR-FORMING COMPOUND CAPABLE OF REACTING WITH A PRIMARY AMINO DEVELOPING AGENT ON PHOTOGRAPHIC DEVELOPMENT, WITH A LOW BOILING WATER-INSOLUBLE ORGANIC SOLVENT FOR THE COLOR-FORMING COMPOUND, SAID LOW-BOILING SOLVENT HAVING A BOILING POINT BELOW 125%C., DISPERSING THE SOLUTION OF COLOR-FORMING COMPOUND AND LOW BOILING ORGANIC SOLVENT IN GELATIN, MIXING THE COLORFORMER DISPERSION WITH A GELATINO-SILVER HALIDE EMULSION FORMING IN A GELATIN CONTINUOUS PHASES, A PACKET DISPERSION OF SAID EMULSION AND COLOR-FORMER, AND THEN MIXING SAID PACKET DISPERSION WITH A SOLUTION OF A SUBSTANTIALLY WATER-INSOLUBLE, LOW MOLECULAR WEIGHT ORGANIC CRYSTALLOIDAL SOLVENT FOR THE COLOR-FORMING COMPOUND AND FOR DYES FORMED THEREFROM, AND WHICH SOLVENT HAS A BOILING POINT ABOVE ABOUT 175*C. AND IS PERMEABLE TO PHOTOGRAPHIC DEVELOPER OXIDATION PRODUCTS, TO FORM A PACKET DISPERSION OF SAID COLOR-FORMING COMPOUND CONTAINING SAID CRYSTALLOIDAL SOLVENT. 